That's a good core army. You'll eventually need aircraft and/or AA units and something to take on war engines, but at 2000 points, you're fine.
I'm a big fan of the Havocs upgrade. It makes the formation expensive, but it packs a ton of firepower and is very durable. They make a great garrison and if you do that you can set them up on Overwatch. It's very good area denial.
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You could use the mounted units (Juggers, Disc Riders, Beastriders) as proxy bikes or, since you have plenty of those, proxy them as daemonic beasts if you want daemons. You could even cut off the riders if you wanted to.
There is a Fanatic Online article about scratch-building Death Wheels. I don't think it's available directly, but I'm sure you could dig up a copy with some internet searching. I haven't priced it out in a while, but I think buying the main parts of it (40K Chaos sprues and such from GW) was something like a minimum of $50, but that gave you enough parts to build about 3.
There are also a variety of potential proxies for other daemon engines if you look around hard enough. Epicomms has a lot of fan sculptors doing stuff so you might be able to get them to trade with you.
Don't use the Androids. They are worth a lot on eBay. People use them to proxy Necrons and they are rare. You could probably sell or trade 2:1 or better for daemons if that's what you're looking for.